Cosmic Apprentice: Dispatches from the Edges of Science

by Sagan, Dorion

  Herndon differs from the geophysicist’s tradition in that he rejects the assumption that our changing Earth has maintained a constant diameter. Continental drift and plate tectonics assume that Earth’s diameter has remained constant at today’s value through time. Herndon argues for a “continental cracking” of the originally continuous lithosphere as Earth decompresses. Hot cracks are forced to widen as the lithosphere breaks and spreads. Seafloor lava, pumice, and basalt spew out. Cold cracks, recognizable to geophysicists as their “subduction zones,” open to become the ultimate repositories for the basalt and the sediments that ride in on it.

  Here, derived from Earth’s early origin as a Jupiter-like gas giant, is a new geoscience paradigm that explains myriad observations attributed to plate tectonics. Herndon’s explanation rejects “mantle-heat convection theory,” for which he claims there is very little evidence. Proposed by Alfred Wegener, John Tuzo-Wilson, Maurice Ewing, Frederick Vine, Drummond Matthews, William R. Dickinson, and others, the grand “continental drift–plate tectonics” paradigm plate-tectonics vision is itself a poster child for interdisciplinary scientific revolutions. Will future scientists look on in dismay at the rigid institutional structures Butler saw emerging, roadblocks that prevented Herndon’s connected suite of professional geophysical concepts of our “indivisible Earth” from being considered?

  Herndon is not the only victim of rigid thought-styles. Another may be the thirty-year rejection of the “heretical” science of the marine zoologist Donald I. Williamson, working out of the Port Erin Marine Station on the Isle of Man. The English historian of biology and medicine Frank P. Ryan tells Williamson’s story of “saltatory evolution” in his recent works on metamorphosis, and the work is also documented in a 2011 film Hopeful Monsters by Robert Sternberg of Imperial College London.22 Animal larvae may evolve by hybridization: fertile crosses between members of different animal phyla may account for extraordinary metamorphoses in the sea. Despite intriguing evidence for these claims,23 there is extreme reticence among professional evolutionary biologists to even print Williamson’s ideas. In detailing evidence for evolution by hybridization, Williamson explicitly disputes Darwin’s central tenet that “descent with modification” (as he termed evolution) occurs slowly by gradual accumulation of naturally selected variations.

  Darwin’s view was made in contrast to Christian views of special creation. Darwin, in The Origin of Species, acknowledges Aristotle’s knowledge of natural selection but dismisses the philosopher and early biologist’s views. Ironically, however, Aristotle dismissed natural selection because he in turn associated it with Empedocles’s pre-Socratic myth that organs once roamed Earth on their own, occasionally joining up and fusing as they were naturally selected into new forms. Aristotle seems to have thrown “the baby out with the bathwater,” and Darwin to have rejected rapid evolutionary change because it smacked of special creation. In both cases we can see these brilliant minds overreacting to protect against the excesses of their ancestors: in Aristotle’s case, against mythic accounts of chimeric unions among men, animals, and gods that violated observations of nature; and in Darwin’s case against the notion of simultaneous creation of species, the monotheistic explanation. Not even the greatest scientists, aware of the need for evidence, are immune from a tendency toward dogma. Ideology inhibits inquiry. New myths are created as people overshoot in their zeal to refute old myths. Everybody needs something to believe in, even nonbelievers.

  Gazing into the spiral of the history of science is a fascinating spectacle: not only do “truths” become “myths,” but, as the spiral of evidence unwinds, some of what formerly was dismissed as myth, with new observations and new methods by new investigators under changed social conditions, sometimes is resuscitated as scientifically valid, with qualification, after all. Science nurtures endless curiosity and further investigation, exploration, and description. Really new scientific truths have come from kooks who need criticism and suffer failures. Beyond the battles of cranks and dogmatists dug deep in their holes are the alliances of skeptics and the curious, able, if evidence warrants, to change their minds. Reexamination, reinterpretation, reevaluation, and reinvestigation are intrinsic. The progress of knowledge through a combination of critical inquiry and open-mindedness is science itself.

  CODA

  After my mother died, her longtime companion, the highly respected Spanish microbiologist Ricardo Guerrero, when I asked him about the character of her rebellious views, mentioned that, though she’s an intellectual heroine in Spain, there were three things about her he refused to discuss there: (1) 9/11, (2) the PNAS affair (in which she, availing herself of her privilege as a member of the National Academy of Sciences, had Williamson’s paper on fertile cross-species unions published in the Proceedings of the National Academy of Sciences,24 and (3) AIDS (where she questioned the canonical HIV-AIDS connection). When I asked him what he thought of her advocacy of Gaia theory, however, he quickly answered that it was one of the greatest scientific theories of the twentieth century. This contrast between Guerrero and the neo-Darwinists (whom Gould called “Darwinian fundamentalists”) exemplifies the existence of the kook–critic continuum of my subtitle: the very progress of science depends on tireless questioning of received opinions, especially when they are both supported by evidence and threaten entrenched assumptions, money flows, and careers. Truth, or its asymptotic representatives, may be stymied but in the long run “will out,” as Shakespeare put it.

  CHAPTER 12

  METAMETAZOA

  LIKE A GRAY GEODE CRACKED OPEN to reveal coruscating crystals of amethyst, the history of science sometimes surprises. Empedocles imagined an ancient world of organs mating and merging with one another to create bizarre half-hewn beasts, the most favorable matches surviving. Aristotle, schooled in Platonic typology and sick of unlikely stories of cross-species mating, metamorphosed mortals, and shape-shifting gods, rejected Empedocles out of hand.

  But the chronological vortex of knowledge’s wayward march turns on itself like a DNA molecule: Now we know that Aristotle, first biologist though he may be, was wrong on both counts. Empedocles’s intuition of natural selection and symbiosis was on the mark. Nothing as ghoulish as crawling pancreas and self-pumping hearts getting it on in the primordial mud, but today’s textbooks teach that our organelles, parts of the cell outside the nucleus, once swam as beings on their own. These are the mitochondria, and they give you the genetic intracellular infrastructure to breathe oxygen, a toxic waste gas first released in massive quantities into the atmosphere by cyanobacteria, which came up with the clever idea of using water to grab their hydrogen atoms. The archaea victimized by bacterial air pollution were saved by bacterial infection. We now celebrate their double victimhood with every breath we take, as their infection evolved into mitochondria at the heart of all animal metabolism and energy use. In retrospect, Empedocles was right. Although there’s no evidence of his “man-faced ox-progeny” that “perished and continue to perish,”1 there are, we could say, “bacteria-bodied archaea-progeny” that “survived and continue to survive.” You are one of them!

  A similar story could be told of the scientific disproof of spontaneous generation. Lazzaro Spallanzani and Louis Pasteur with curved glass flasks protecting inoculation proved that life doesn’t arise from nonlife—meat doesn’t beget maggots, mice don’t defrag from rags. Yet, flash forward once more, to the origins-of-life experiments showing that amino acids naturally form when ammonia and other hydrogen-rich compounds are exposed to an energy source, and the possibility arises that life can occur from nonlife and not just be seeded by spores from the air (or space; see chapter 4). As in the T. S. Eliot poem, we return to a different floor of the expanding vortex, the Escherian staircase of science. Another example is the great Sphinx at Giza, whose chimeric mancat body is made of stone, yellowish calcium carbonate studded with nummulites, “coin stones” that Herodotus thought were fossilized lentils but are actually the remains of foraminifera. Li
ve forams fill the oceans, their tiny spiked carbonate bodies usually no bigger than a pinhead but sometimes growing to inches without giving up their status as single cells. Cut transversely, they show spirals. And many of their species, whose variety tracks the hidden treasure of fossil fuels, are symbiotic: Again the baroque vortex turns, the mythological blend that is the Sphinx is a creature of the imagination, is made up, but its real body is made up of the fossil remains of real chimeras, as are the Great Pyramids themselves, 40 percent of whose yellow limestone consists of fossil forams, many of them symbiotic with specific species of diatoms and dinomastigote algae that floated in the Tethys Sea, during the Eocene, more than thirty million years ago.

  The oldest known sphinxes are from Anatolia, Turkey, and are over nine thousand years old. The oldest fossils of possibly chimeric beings, such as acritarchs, are over three billion years old. More recently, in attempting an untested sleight with a piece of Dominican amber, I dropped it on the floor of my mother’s lab at the Morrill Science Center at the University of Massachusetts. This missed trick with the fossilized tree sap on loan from David Grimaldi of the American Museum of Natural History paved the way for thin-section electron microscopy. The cracked amber revealed a twenty-million-year-old termite whose hindgut was full of petrified swimmers--spirochetes, cellulose-digesting protists, and the spore-forming filamentous bacterium, Arthromitus—equivalent to Bacillus cereus, identical except for two or three plasmids, which are DNA coiled into tight rings, to Bacillus anthracis, the causative agent of anthrax.2

  Life’s tenure on this planet has been so long, and its grip so tight, that many things that seem to be singular organisms reveal themselves—like the Sphinx or that tawny piece of Miocene butterscotch cracked open like Humpty Dumpty to reveal the termite Mastotermes electrodominicus, now known only as a living fossil from northern Australia, or the fossil itself, containing a miniature Pompeii in its swollen hindgut—to be constructed of other life-forms. As the helix of history turns, we descend deeper along this escalator into life’s ancient forms, its ghostly archive and living tombs. It slipped out of my hand, but that magical piece of amber made the cover of Science News, one of science’s leading magazines.3

  HOW WILL THE BODY AND ITS LIFE come to have been construed by the future of biology? And more important, how will these be construed by a mythopoiesis and popular mythology whose social birthright now, through the midwife of contemporary biology, may create the “facts” from which a common future understanding will come? Transformations of classical models are already under way in contemporary biology, and here I look at three of them: Gaia theory (geophysiology or Earth system science), symbiotic evolution (symbiogenetics), and bacterial omnisexuality (hypersexuality).

  It is necessary, first of all, to distinguish the tenor of a “new biology,” whose theoretical sources are Gaia, symbiosis, and gene-trading bacteria, from the tenor of the more traditional biology for which the paradigm of individuality is the animal body. Modern biology, informed by cellular ultrastructure through electron microscopy and detailed knowledge of gene sequences, has supplemented or even negated the long-standing division between plant and animal kingdoms.4 Although vying for acceptance and mutually inconsistent, the two most favored current phylogenies split life into either three domains or five kingdoms. The five-kingdom classification system still reserves a place for the kingdoms Plantae and Animalia (both subsumed within the superkingdom Eukarya).

  Carl R. Woese’s three-trunked tree of life, based on typical sequences of RNA in the ribosomes of cells, contains no separate kingdoms for plants or animals, for it lumps both within the eucarya (organisms composed of cells with nuclei), reserving two separate taxa (archaea, which Woese used to call archaebacteria, and bacteria, formerly eubacteria) for the rest of life. Molecular biology and microbiology have not only confirmed Charles Darwin’s paradigm-shifting argument that we are animals but have also provided evidence that the most fundamental fence in life lies not between plants and animals but between eukaryotes—cells with nuclei, mitochondria (and, in the case of algae and plants, plastids)—and prokaryotes, also known as monerans or bacteria. Homo sapiens clings to its crown as the walls of its kingdom come crumbling down. Moreover, each eukaryotic “animal” cell is, in fact, an uncanny assembly, the evolutionary merger of distinct prokaryotic metabolisms. Strictly speaking, there is no such thing as a one-celled plant or animal.

  Easily recognizable life-forms appear only at the middle range. If we step back from, or come closer to, the living canvas, organisms blend into a pointillist landscape in which each dot of paint is also alive. In short, all previous biology has been grossly zoocentric.

  Although psychoanalysis and phenomenology and their popular offshoots have disturbed a monolithic conception of mind, a monolithic notion of “the” body remains largely intact. In classical medicine, the body is considered a type of unity. Cancer, paradigmatically, but other diseases as well, are discussed with the rhetoric of war: the body is “attacked” and “invaded”; it puts up “defenses” and “fights back.” This medical model of the body-as-unity-to-be-preserved, though, of the body proper, is besieged by the new biology.

  A radical rerendering of the body is under way in accordance with three models from the new biology, namely, symbiosis, Gaia, and prokaryotic sex. This reformulation augurs a breakdown of the medically proper animal body, which is simultaneously driven in at least two new directions, one post-structural and the other medieval-microcosmic in terms of extended selves within a living environment. Gaia refers to the biosphere understood not as environmental home but as body, as physiological process. Prokaryotic sex, or bacterial omnisexuality, refers to the fluid genetic transfers, by definition sexual, among continuously reproducing bacteria.

  The consonance with certain post-structuralisms occurs in that the new biology parts company with the unitary self assumed in the zoocentric model. The expression “medieval-microcosmic” is inadequate but suggests the possibility of correspondences among prokaryotic, eukaryotic, zoological, and geophysiological (Gaian) levels. It now appears that a type of individuality has appeared at each of these levels. Both spatially and temporally more inclusive, Gaia and animals dwell within a holonomic continuum, superordinating the smaller beings of which they are made.

  THE BODY AS CHIMERA

  The body as seen by the new biology is chimerical. Instead of the tripartite division of that mythical creature of antiquity, the chimera, into lion, goat, and snake, the animal cell is seen to be a hybrid of bacterial species—although the word species, as seen below, is not that apt when applied to bacteria. Like that many-headed beast, the microbeast of the animal cell combines into one entity bacteria that were originally freely living, self-sufficient, and metabolically distinct. Mitochondria populate and energize virtually all eukaryotic cells. These specialized cell parts respire; they take up oxygen and produce carbon dioxide, making ATP (adenosine triphosphate), a kind of molecular capacitor storing energy within cells. It is now widely accepted among biologists that these tiny intracellular power stations were once autonomous respiring bacteria. Eukaryotic cells evolved over a billion years ago, probably when respirers entered and did not kill but were incorporated by larger anaerobic archaea. The archaea include sulfur-breathing, acid-resistant, and heat-tolerant extremophiles—an impressive range of resistances that may reflect an ancient ability to survive hot temperatures and meteoritic bombardments of the early Earth. Over time, the two distinct metabolisms merged, and the new incorporated cells produced more and hardier cells than either line of their unincorporated relatives.

  Some intriguing signs recall the ancient free lives of mitochondria. Although they lie outside the cell’s nucleus, they have their own genetic apparatus, including their own DNA, messenger RNA, transfer RNA, and ribosomes enclosed in mitochondrial membranes. Unlike the DNA of the nucleus, but like bacterial DNA, mitochondrial DNA is not coated by histone protein. Mitochondria assemble proteins on ribosomes very similar to t
he ribosomes of bacteria. Both mitochondrial ribosomes and those of respiring bacteria tend to be sensitive to the same antibiotics, such as streptomycin. Perhaps most telling, mitochondria reproduce on their own timetable and in their own way, forgoing the complex mitosis of the nucleus for a simple bacterium-like division. They engage in the nonsystematic genetic transfer that characterizes bacterial sex. All in all, they behave like prokaryotic captives.

  As early as 1893, the German biologist A. F. W. Schimper proposed that the photosynthetic parts of plant cells came from cyanobacteria (often still called blue-green algae, but the term is a misnomer, since they have no nuclei in their cells). The French biologist Paul Portier believed by 1918 that mitochondria are the descendants of bacteria that had become lodged within the cells of animals and plants. In the first quarter of this century, the American anatomist Ivan Wallin and the Russian scholar-biologist Konstantin S. Mereschovsky had independently come to the same conclusion. In 1910 Mereschovsky, who taught at the University of Kazan, published an essentially contemporary view of the origin of eukaryotic cells from various kinds of bacteria.5

  Experiments at isolating the putative bacterial partners, however, have always failed; the evidence for cooperation rather than parasitism was overlooked and dismissed as “sentimentalism.” Herbert Spencer equated the necessary evils of competition with an eminently desirable social progress, and Thomas Huxley referred to the animal world as a “gladiator’s show”; Pyotr Kropotkin wrote Mutual Aid, and others implicitly linked evolutionary ideas of symbiosis to labor unions, mutualistic societies, and socialist ideas.